Dielectric ceramic polarizer

Abstract

A dielectric ceramic substrate or block contains, at least, two kinds of metal ions, and a dielectric constant in the substrate or block changes continuously or step by step as a function of position. The metal ions contained in the dielectric ceramic material are, at least, two kinds which are selected from the group consisting of Mg, Ca, Sr, Ba, Zn, Pb, Bi, Y, La, Ce, Nd, Sm, Gd, Er, Ti, Zr, Sn, Si and Mn, and the dielectric constant +531 changes in the range of 7</=+531 </=90. This dielectric ceramic material is used in a dielectric substrate for a stripline device, a dielectric substrate for a monolithic IC and a dielectric block for a polarizer. For example, the dielectric substrate for a stripline device, it is so formed that a dielectric constant at its center portion is constant, and becomes smaller step by step or continuously toward its ends. For forming a stripline on the dielectric substrate, when the characteristic impedance is to be constant, a line width at a center portion of the dielectric substrate is narrow and it becomes wider toward the ends.

What is claimed is: 
     
       1. A dielectric ceramic polarizer, comprising a ceramic material, said ceramic material having a composition and thereby a dielectric constant which change as a function of position with respect to said polarizer, said polarizer comprising: an elongated ceramic body having a longitudinal axis; and along said longitudinal axis, said elongated body having a main portion and having tapered portions formed at opposite ends of said main portion;   said elongated ceramic body having a cross-section in a direction which is transverse to said longitudinal axis and being symmetrical in said transverse direction, and said composition and thereby said dielectric constant change in said transverse direction;   wherein said body has a first inclination portion and a first uniform portion, said first inclination portion and first uniform portion being generally flat, being disposed in contact with each other and extending parallel to said longitudinal axis;   said first inclination portion having a first region with a first dielectric constant, and a second region with a second dielectric constant which is lower than said first dielectric constant, and   said first uniform portion having a third dielectric constant which is lower than said second dielectric constant.   
     
     
       2. A dielectric ceramic polarizer as in claim 1, comprising a ceramic material containing, at least, two different metal ions, wherein the metal ions are selected from the group consisting of Mg, Ca, Sr, Ba, Zn, Pb, Bi, Y, La, Ce, Nd, Sm, Gd, Er, Ti, Zr, Sn, Si and Mn, and said dielectric constant (.di-elect cons.) is in the range of 7≦.di-elect cons.≦90. 
     
     
       3. A dielectric ceramic polarizer in accordance with claim 1, further comprising a second uniform portion, wherein said first and second uniform portions sandwich said first inclination portion. 
     
     
       4. A dielectric ceramic polarizer in accordance with claim 3, further comprising a third region within said first layer, said third region having said second dielectric constant, wherein said second and third regions sandwich said first region and are disposed respectively adjacent to said first and second uniform portions. 
     
     
       5. A dielectric ceramic polarizer in accordance with claim 4, wherein said second and third regions have a range of dielectric constant which decreases between said first and said third dielectric constant. 
     
     
       6. A dielectric ceramic polarizer in accordance with claim 3, wherein said first inclination portion is substantially at said longitudinal axis. 
     
     
       7. A dielectric ceramic polarizer in accordance with claim 3, wherein said first inclination portion is spaced away from said longitudinal axis. 
     
     
       8. A dielectric ceramic polarizer in accordance with claim 3, further comprising second and third inclination portions which are disposed respectively adjacent to said first and second uniform portions and thereby sandwich said first and second uniform portions as well as said first inclination portion. 
     
     
       9. A dielectric ceramic polarizer in accordance with claim 8, wherein said first inclination portion is substantially at said longitudinal axis. 
     
     
       10. A dielectric ceramic polarizer in accordance with claim 3, further comprising a second inclination portion disposed adjacent to said second uniform portion, and a third uniform portion disposed adjacent to said second inclination portion. 
     
     
       11. A dielectric ceramic polarizer in accordance with claim 10, wherein said first inclination portion and said second inclination portion are both spaced away from said longitudinal axis. 
     
     
       12. A dielectric ceramic polarizer in accordance with claim 1, wherein said main portion is substantially cylindrical and said tapered portion are substantially conical. 
     
     
       13. A dielectric ceramic polarizer in accordance with claim 1, wherein said main portion is substantially square and said tapered portion are substantially pyramidal. 
     
     
       14. A dielectric ceramic polarizer in accordance with claim 1, wherein a cross-sectional shape of said main portion is a regular polygon and a cross-sectional shape of said tapered portions is a regular polygon with the same included angles as said cross-sectional shape of said main portion. 
     
     
       15. A dielectric ceramic polarizer in accordance with claim 1, wherein said dielectric constant within said main portion changes substantially only as a function of position. 
     
     
       16. A dielectric ceramic polarizer in accordance with claim 1, wherein said dielectric constant within said main portion changes as a function of position when said main portion is at a constant temperature. 
     
     
       17. A dielectric ceramic polarizer in accordance with claim 5, wherein said dielectric constant within said second and third regions changes continuously as a function of position. 
     
     
       18. A dielectric ceramic polarizer in accordance with claim 5, wherein said dielectric constant within said second and third regions changes incrementally as a function of position.